Navigating the Model Object Using a GUI
The usual approach to navigate through the model object in a graphical user interface (GUI) is to load the model object at the COMSOL Desktop. Then transfer the model object from the COMSOL Multiphysics server to the COMSOL Desktop as in Sharing the Model Between the COMSOL Desktop® and the MATLAB® Workspace.
An alternative approach is to call the function mphnavigator that displays the model object information in a MATLAB® GUI. To run the function at the MATLAB prompt, enter the command:
mphnavigator
This command pops up a MATLAB GUI as in this figure:
When starting mphnavigator without any arguments it will use the model stored in the model variable. If the COMSOL model objected is not stored in the MATLAB variable model enter the command:
mphnavigator(<modelvar>)
where <modelvar> is the variable name in MATLAB that contains the model.
The appearance and behavior of the mphnavigator window depend on the version of MATLAB. Using MATLAB version 2020a or newer will show an updated user interface based on App Designer. These user interfaces can be resized and in many cases support a faster workflow compared to previous versions.
The Menu Bar Items
In the File menu you will find file handling commands such as Open and Save as to load a new model object in the COMSOL Multiphysics server and update the Model Object Navigator window and save the current model object in the MPH-file format, respectively. If you want to visualize the current model object in the COMSOL Desktop, click Launch COMSOL Multiphysics. Click Show model thumbnail to show the model thumbnail in a separate window.
In the Tools menu you will find additional functionality to inspect the model. Click Plot to displays the geometry, the mesh, or a plot group in a MATLAB figure. This button is only active when one of the corresponding node in the model tree is selected. Select Search to open the Model Search window where you can search for expressions or tags in the model object (see Finding Model Expressions). Select Solutions to open the Solution Info window that displays the solution object available in the COMSOL Multiphysics model object. Select Warnings and Errors to list the error or warning nodes available in the model object (see Handling Errors and Warnings). Click Add report (also accessible with the shortcut icon below the menu list) to generate a report node in the model; you can choose between brief, intermediate, or complete reports. Select Write report (also accessible using the icon ) to write a report, which has been previously added to the model, in a document. This opens the Run Report window where you can specify the report node to run and the report settings such as the filename and the output format.
Using LiveLink for MATLAB, it is quite common to run a specific node in a loop. To automatically get the corresponding code ready to be pasted in a code editor, click Copy code: loop. This will generate the following commands:
tag1 = <feattag1>;
tag2 = <feattag2>;
tags = cell(model.geom(tag1).feature(tag2).feature.tags);
for i=1:length(tags)
  obj = model.geom(tag1).feature(tag2).feature(tags{i});
end
where <feattag1> and <feattag2> are the feature tags to reach the selected feature in the model.
In the Options menu you can set some preferences for the Model Object Navigator window.
Select Automatic update to get the model tree and properties automatically updated as the current model object is changed. A manual update can be achieved by clicking in the toolbar.
Select Use component syntax to include the component in the COMSOL API command. To get the property value as a string when clicking the Copy get button, select Get property as string. You can also select Show name to display the node name in the model tree instead of the tag node only.
The Help menu you can get the help of a selected node in the model tree (Help button or ) as well as the corresponding API help (API Help button or ).
The Model Tree Section
The Model Tree section has the list of the nodes of the model object. Use the scrollbar to the right to scroll down the list and click the + icon to expand the model object feature nodes.
When a feature node is selected, its associated command is listed just beneath the model tree. Click Copy to copy syntax to the clipboard and then paste it in your script.
The Model Tree list is different from the Model Builder tree available in the COMSOL Desktop. This is because mphnavigator displays all feature nodes as seen in the COMSOL API which does not use the same filter as in the COMSOL Desktop to order the available feature nodes.
The Properties Section
This section includes a table that list all the properties of a selected feature node.
The Properties and the Value columns list the properties of the selected feature node and the associated values respectively. The Allowed Value column list the allowed value for the corresponding property.
Not all feature node returns a list of allowed value for the properties.
Click Copy set, or Copy get, to copy to the clipboard the command that sets the selected property to its current value, respectively get the value of the currently selected property. Click Copy Table to copy the entire properties table to the clipboard, then paste into a text or spreadsheet editor. To copy a selected cell in the table, click Copy. Using the Float window button you can open the Properties table in a separate window.
The Methods Section
The Methods section lists all the methods associated to the feature node selected in the Model Tree section
Select a method in the list to get its associated syntax at the button of the Methods section. Use the Copy button to copy the syntax to the clipboard. Click Copy call to copy the method syntax associated to the selected feature node, the syntax is ready to use at the MATLAB prompt.